import Vue from 'vue';
import { on } from './dom';

const nodeList = [];
const ctx = '@@clickoutsideContext';

let startClick;
let seed = 0;

if (!Vue.prototype.$isServer) {
  on(document, 'mousedown', e => {
    startClick = e;
  });
  on(document, 'mouseup', e => {
    nodeList.forEach(node => node[ctx].documentHandler(e, startClick));
  });
}

function createDocumentHandler(el, binding, vnode) {
  return function(mouseup = {}, mousedown = {}) {
    if (
      !vnode ||
      !vnode.context ||
      !mouseup.target ||
      !mousedown.target ||
      el.contains(mouseup.target) ||
      el.contains(mousedown.target) ||
      el === mouseup.target ||
      (vnode.context.popperElm &&
        (vnode.context.popperElm.contains(mouseup.target) || vnode.context.popperElm.contains(mousedown.target)))
    ) {
      return;
    }
    if (binding.expression && el[ctx].methodName && vnode.context[el[ctx].methodName]) {
      vnode.context[el[ctx].methodName]();
    } else {
      el[ctx].bindingFn && el[ctx].bindingFn();
    }
  };
}

/**
 * v-clickoutside
 * @description 点击元素和其对应的popperElm外面才会触发的事件
 */
export default {
  bind(el, binding, vnode) {
    nodeList.push(el);
    const id = seed++;
    el[ctx] = {
      id,
      methodName: binding.expression,
      bindingFn: binding.value,
      documentHandler: createDocumentHandler(el, binding, vnode)
    };
  },
  update(el, binding, vnode) {
    el[ctx].methodName = binding.expression;
    el[ctx].bindingFn = binding.value;
    el[ctx].documentHandler = createDocumentHandler(el, binding, vnode);
  },
  unbind(el) {
    const len = nodeList.length;
    for (let i = 0; i < len; i++) {
      if (nodeList[i][ctx].id === el[ctx].id) {
        nodeList.splice(i, 1);
        break;
      }
      delete el[ctx];
    }
  }
};
